Antitrust questions put a useful spotlight on the privacy issues of online profiling by those who sell advertising on the Web. These questions apply not just to Google but to any site that uses personal information and behavior data to develop and use individual users' profiles. But simply assuring advertisers a fair marketplace won't be sufficient to guarantee user privacy. We know that many users are willing to give up some privacy protection for short-term convenience, but we shouldn't conclude from these chokes that privacy means the sum total of whatever people end up choosing.